This is a new application for an institutional training program in Pediatric Gastroenterology designed to produce investigators trained for a successful career in basic or clinical research in the area of pediatric gastroenterology. Trainees will be at the post-doctoral level, generally with an MD, supported for two years of basic or clinical research training. This grant allows for recruitment of two MD or PhD trainees each year for a total of two years of training each. The program will place a strong emphasis on several pathways of basic science research including molecular biology, immunology, virology and mechanisms of liver cell injury. The rationale for inclusion of these approaches is that they are increasingly important in research in pediatric gastroenterology and developmental biology. The mentors (15 MD's, 2 MD/PhD's, 7 PhD's) represent a multidisciplinary group with a demonstrated focused interest in areas of research that are directly applicable to pediatric gastroenterology. In addition, they have demonstrated success at training clinician scientists or clinical research level physicians. The Pediatric Gastroenterology, Hepatology and Nutrition Program at the University of Colorado has an excellent track record in training academic physicians with all fellows receiving at least two years of dedicated research training. This application seeks to increase funding for basic and clinical research programs for an exceptionally competitive pool of fellow applicants. The nature of administrative decisions (selection of trainees, selection of mentors and research projects) are directed by the Program Director through the Selection and Research Committees. The training for MD fellows includes course work designed for introduction to research techniques and the Mini-Certificate program in Clinical Research through the University of Colorado Health Sciences Center. Each fellow has a designated mentor and research committee, and is required to present a written research proposal, and undergoes periodic reviews of progress. The trainees are selected from a competitive applicant pool at the University of Colorado. This program has demonstrated success with 55% of MD's remaining active in research with success in research funding. This proposal will allow amplification of the historic success of this program in training future academic pediatric gastroenterologists